BBC Knowledge June 2017

PHOTOS: GETTY ILLUSTRATIONS: RAJA LOCKEY

1. WATER
   You can only survive three days without
   water. Scavenge the beach for containers
   and set each one in the sand, at the bottom
   of a wide, shallow pit. Line the sides
   with palm leaves, arranged so that rain
   drips into the bottles. While you wait
   for rain, explore the island to look
   for streams.


2. FOOD
   Coconuts are a great food source. Wedge
   one on the ground, with the pointed end
   facing upwards. Find the largest rock you
   can lift and drop it onto the coconut to break
   the husk fibres apart. One survivor of the
   2004 tsunami ate nothing but coconuts for
   25 days before being rescued,
   so your chances are good!


3. SHELTER
   Unless you can sleep, you will lose the ability
   to concentrate, plan and stay motivated
   after just one or two nights. A bundle
   of small branches spread on the ground
   and covered with palm leaves is still
   better than sleeping directly on the sand.
   After that, build a low bed frame by tying
   saplings together..

How could I survive being washed up on a desert island?

THE THOUGHT EXPERIMENT

During the 1990s, astronomers measuring the rate

at which the Universe is expanding made a shock

discovery: it’s actually accelerating, as if the whole

cosmos is being propelled by some invisible source

of energy. This is so-called dark energy and its origin

is one of the deepest mysteries in science. Various

explanations have been put forward, with arguably

the simplest being that it’s a manifestation of so-called

quantum vacuum processes. According to the laws

of the subatomic world, there is always some uncertainty

about the amount of energy filling even empty space.

This vacuum fluctuation energy has been detected in

the lab, and theorists have shown it can have

the ‘anti-gravitational’ effects of dark matter. So far,

however, they have struggled to produce a detailed

theory of its cosmic effects. This has led to suggestions

that dark energy may simply be a force-field left over from

the Big Bang. Sometimes called quintessence,

it’s capable of getting stronger over time, but again

details remain elusive. There have even been claims that

dark energy is leaking out from hidden extra dimensions

of space that failed to expand following the Big Bang.

Until there’s a breakthrough in the underlying theory,

however, all this is little more than speculation. RM

WHAT IS

DARK ENERGY?

June 2017 13

The Dark Energy

Camera in Chile helps

scientists study the

expansion of space